Question

Among the following which one does not act as intermediate in Hoffmann rearrangement

• A. $RNCO$
• B. $RCO\ddot{N}$
• C. $RCO\ddot{N}HBr$
• D. $RNC$

Answer 1

The correct option is D $RNC$

Solution:- (D) $RNC$

Hoffmann bromamide reaction take pace as follows-

$R-\stackrel{\underset{||}{O}}{C}-N{H}_2\stackrel{{Br}_2+KOH}{\to }RCONHBr\stackrel{KOH}{\to }[R-\stackrel{\underset{||}{O}}{C}-N]⟶R-N=C=O\stackrel{H_{2}O}{\to }R-N{H}_2$

Hence $RNC$ does not act as intermediate in Hoffmann rearrangement.